Validated TLC and HPLC Stability-Indicating Methods for the Quantitative Determination of Dapsone

JPC – Journal of Planar Chromatography – Modern TLC - Two stability-indicating chromatographic methods were developed for the analysis of dapsone in presence of its oxidative...     

Development and Validation of Stability-Indicating HPLC Methods for Quantitative Determination of Pravastatin,Fluvastatin, Atorvastatin,and Rosuvastatin in Pharmaceuticals

Abstract

High-performance liquid-chromatographic (HPLC) methods were validated for determination of pravastatin sodium (PS), fluvastatin sodium (FVS), atorvastatin calcium (ATC), and rosuvastatin calcium (RC) in pharmaceuticals. Two stability-indicating HPLC methods were developed with a small change (10%) in the composition of the organic modifier in the mobile phase. The HPLC method for each statin was validated using isocratic elution. An RP-18 column was used with mobile phases consisting of methanol–water (60:40, v/v, for PS and RC and 70:30, v/v, for FVS and ATC). The pH of each mobile phase was adjusted to 3.0 with orthophosphoric acid, and the flow rate was 1.0 mL/min. Calibration plots showed correlation coefficients (r) > 0.999, which were calculated by the least square method. The detection limit (DL) and quantitation limit (QL) were 1.22 and 3.08 µg/mL for PS, 2.02 and 6.12 µg/mL for FVS, 0.44 and 1.34 µg/mL for ATC, and 1.55 and 4.70 µg/mL for RC. Intraday and interday relative standard deviations (RSDs) were <2.0%. The methods were applied successfully for quantitative determination of statins in pharmaceuticals.     

水体硝酸盐检测方法的研究进展

硝酸盐是活性氮中导致水体富营养化以及危害人体健康的重要形式,因此水体硝酸盐的检测在水体质量表征中一直备受关注。水体硝酸盐的常规检测主要是借助传统的分光光度法,这类方法经典权威,分析结果可靠,然而大都破坏样品、耗时、成本高,并且在硝酸盐定量分析中的干扰因素也较多。近年来,现代光谱技术的应用得到迅速发展,也已经在水体硝酸盐检测中有了较好的尝试,为海量水体质量信息的获取提供新的技术支撑。在介绍了水体硝酸盐检测方法的基础上,就水体硝酸盐检测方法的研究进展以及现代光谱技术在水体硝酸盐检测中的应用前景进行了归纳、分析和介绍,并指出傅里叶变换衰减全反射光谱(FTIR-ATR)可以实现快速适时的水体信息定量传感和质量监测,在水体硝酸盐的分析实践中具有广阔的应用空间。     

Development and Validation of a Stability-Indicating Assay Method for Naftopidil

JPC – Journal of Planar Chromatography – Modern TLC - A sensitive, selective, precise, and stability-indicating high-performance thin-layer chromatography (HPTLC) method for the...     

锗元素测定方法综述

锗在国防工业、航空航天和通信等领域中的战略性,锗含量的测定对于保证材料质量和满足国际标准至关重要。本文综述了锗含量测定方法的多种技术,包括分光光度法、原子荧光光谱法、原子吸收光谱法、电感耦合等离子体原子发射光谱法、电感耦合等离子体质谱法以及滴定法。在每个检测方法的介绍中,详细探讨了方法的原理、前处理步骤以及应用范围,并分别总结了各个方法的优势和不足。最后,强调了锗含量测定方法的意义,特别是在满足出口监管和促进科学研究方面的作用。同时对锗元素的测定方法进行了展望,为未来的发展提供了参考方向。     

Validated Stability-Indicating Chromatographic Methods for the Determination of Veralipride in Presence of Its Degradation Products

Two sensitive and selective chromatographic methods were developed and validated for determination of veralipride in presence of its degradation products. Forced degradation studies were performed, using HCl, NaOH and 3% H₂O₂. The first method is based on thin-layer chromatographic separation of the intact drug spot from its degradation, followed by densitometric measurements. The second method is based on isocratic liquid chromatographic separation of the studied drug from its degradation on a reversed phase C₁₈ column. The proposed LC method was utilized to investigate the kinetics of alkaline degradation process of the selected drug at different temperatures.     

Development and Validation of a Stability-Indicating LC Method for Curcumin

A simple, isocratic, stability-indicating liquid chromatographic method for quantitative determination of curcumin was successfully developed. The chromatographic separations were achieved using a Hi-Q-Sil C18; 4.6 mm × 250 mm and 10 μm particle size column employing acetonitrile and acetate buffer (pH 3.0; 60: 40, v/v) as the mobile phase. The analyte was subjected to acidic, basic, oxidative, thermal and photo degradation. The method was validated with respect to linearity, precision, accuracy, limit of detection and limit of quantification. Curcumin was detected by UV-Vis detector at 425 nm whereas the degradation products were detected at 280 nm. The method was linear over the concentration range of 1–10 μg mL^?1. The limit of detection was found to be 0.06 μg mL^?1 and the quantification limit was 0.21 μg mL^?1. Considerable degradation of the analyte was observed when it was subjected to alkaline conditions. Accuracy, evaluated as recovery, was in the range of 97–103%. Intra-day precision and intermediate precision showed relative standard deviations <1% and <2% respectively.     

Multiarm Star Polymers. Fundamental Aspects. A Review

Doklady Chemistry - The review is devoted to the analysis of the currently available data in the field of the molecular organization of multiarm stars, macromolecules-particles characterized by the...     

抗胆碱能药物曲司氯铵分析方法进展

曲司氯铵是一种抗胆碱能药物,用于治疗膀胱过度活动症引起的尿频和尿失禁.曲司氯铵较其它药物耐受性更高,病人使用更为安全,但其检验方法报道不多.对曲司氯铵的分析方法(包括滴定法、紫外分光光度法、高效液相色谱法、气相色谱法、液体闪烁计数法等)进行了评述和展望.     

Development of a Validated Stability-Indicating LC Method for Nitazoxanide in Pharmaceutical Formulations

A reversed-phase liquid chromatographic (LC) method was developed for the assay of nitazoxanide (NTZ) in solid dosage formulations. An isocratic LC separation was performed on a Phenomenex Synergi Fusion C₁₈ column (250 mm × 4.6 mm, i.d., 4 μm particle size) using a mobile phase of 0.1% o-phosphoric acid solution, pH 6.0: acetonitrile (45:55, v/v) at a flow rate of 1.0 mL min⁻¹. Detection was achieved with a photodiode array detector at 240 nm. The detector response for NTZ was linear over the concentration range from 2 to 100 μg mL⁻¹ (r = 0.9999). The specificity and stability-indicating capability of the method were proved using stress conditions. The RSD values for intra-day precision were less than 1.0% for tablets and powder for oral suspension. The RSD values for inter-day precision were 0.6 and 0.7% for tablets and powder for oral suspension. The accuracy was 100.4% (RSD = 1.8%) for tablets and 100.9% (RSD = 0.3%) for powder for oral suspension. The limits of quantitation and detection were 0.4 and 0.1 μg mL⁻¹. There was no interference of the excipients on the determination of the active pharmaceutical ingredient. The proposed method was precise, accurate, specific, and sensitive. It can be applied to the quantitative determination of drug in tablets and powder for oral suspension.     

Development of a Stability-Indicating LC Assay Method for Determination of Chloroquine

A simple and rapid development of a stability-indicating LC method for determination of chloroquine diphosphate in the presence of its hydrolysis, oxidative and photolysis degradation products is described. Stress testing showed that chloroquine diphosphate was degraded under basic conditions and by photolytic treatment but was stable under the other stress conditions investigated. Separation of the drug from its degradation products was achieved with a Nova Pack C18 column, 0.01 M PIC B7 and acetonitrile (40:60 v/v) pH 3.6, as mobile phase. Response was linear over the range 0.08–5.70 μg mL⁻¹ (r = 0.996), with limits of detection and quantification (LOD and LOQ) of 0.17 and 0.35 μg mL⁻¹, respectively.

     

A Stability-Indicating LC Method for Assay of Topotecan Hydrochloride

This paper describes the development of a stability-indicating high-performance liquid chromatographic (HPLC) method for quantitative determination of topotecan hydrochloride, a semi-synthetic derivative of camptothecin and anti-tumor drug with topoisomerase I-inhibitory activity. Chromatographic separation was achieved on a C₁₈ column with a mixture of phosphate buffer and acetonitrile as mobile phase. The method was validated for linearity, accuracy, precision, and robustness. Forced degradation studies were performed by treating bulk samples of topotecan hydrochloride with acid (0.5 M hydrochloric acid), base (0.5 M sodium hydroxide), oxidizing agent (10% v/v hydrogen peroxide), heat (60 °C), and UV light (254 nm).     

Chemiluminescence and Spectrofluorimetric Methods for Determination of Fluoroquinolones: A Review

Fluoroquinolones are an important and extensively studied group of compounds. Newer generations of fluoroquinolones are being developed to enhance the antimicrobial spectrum and pharmacological properties of these antimicrobials. Various analytical methods including chromatographic, voltametric, titrimetric, potentiometric, spectrophotometric, and so forth have been reported for analysis of these drugs. However luminescence and spectrofluorimetric methods continue to hold much significance as they are simple, economical, and sensitive as compared to most of the other methods. This led us to review the luminescence and spectrofluorimetric methods described for the analysis of this important class of drugs either per se, in dosage forms, or in biological fluids.     

催产素检测方法的研究进展

催产素(Oxytocin)是一种重要的短肽类神经激素,在人类认知和社会行为中发挥着关键的作用。因此,建立高灵敏度、高特异性、快速、准确的生物样品中催产素的检测方法,对阐明催产素的生物功能、作用机理和探索相关精神疾病的治疗方法有重要的意义。本文介绍了目前已发展的催产素的各种定量检测方法及相关应用,并对未来该领域的迫切需求和技术难点进行了评述和展望。     

Comparison of Two Stability-Indicating Chromatographic Methods for the Determination of Mirabegron in Presence of Its Degradation Product

Mirabegron is a novel β₃-adrenoceptor agonist containing an amide group. It was subjected to stress conditions of acidic and alkaline hydrolyses. The hydrolytic degradation product was isolated and its structure was confirmed using mass and IR spectrometry. Two stability-indicating chromatographic methods have been proposed for the determination of mirabegron. TLC method was applied using silica gel as stationary phase and chloroform–methanol–ammonia (9.0:1.0:0.1 by volume) as the mobile phase, and chromatograms were scanned at 250 nm. Accurate determination of the drug was achieved over the concentration range of 2–12 μg per band. In addition, an isocratic HPLC method was developed on Agilent C18 column (150 mm × 4.5 mm I.D., particle size 5 µm) using ethanol-phosphate buffer pH 2.5 (30:70, by volume) as a mobile phase with flow rate of 1 mL min^?1.The intact drug was detected at 250 nm with running time less than 5 min. Mirabegron was determined accurately in a concentration range of 1–25 µg mL^?1. The proposed chromatographic methods were applied successfully for the assay of mirabegron in pharmaceutical dosage form and both methods were validated as per the International Conference on Harmonization guidelines and statistically compared with a reported gradient HPLC method.     

Stability-Indicating Chromatographic Methods for Simultaneous Determination of Mosapride and Pantoprazole in Pharmaceutical Dosage Form and Plasma Samples

Simple, sensitive, selective, precise, and stability-indicating thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) methods for the determination of mosapride and pantoprazole in pharmaceutical tablets were developed and validated as per the International Conference on Harmonization guidelines. The TLC method employs aluminum TLC plates precoated with silica gel 60F₂₅₄ as the stationary phase and ethyl acetate/methanol/toluene (4:1:2, v/v/v) as the mobile phase to give compact spots for mosapride (R _f 0.73) and pantoprazole (R _f 0.45) separated from their degradation products; the chromatogram was scanned at 276 nm. The HPLC method utilizes a C18 column and a mobile phase consisting of acetonitrile/methanol/20 mM ammonium acetate (4:2:4, v/v/v) at a flow rate of 1.0 mL min⁻¹ for the separation of mosapride (t _R 11.4) and pantoprazole (t _R 4.4) from their degradation products. Quantitation was achieved with UV detection at 280 nm. The same HPLC method was successfully used in performing calibrations in lower concentration ranges for both drugs in human plasma using ezetimibe as internal standard. The methods were validated in terms of accuracy, precision, linearity, limits of detection, and limits of quantification. Mosapride and pantoprazole were exposed to acid hydrolysis and then analyzed by the proposed methods. As the methods could effectively separate the drugs from their degradation products, these techniques can be employed as stability-indicating methods that have been successively applied to pharmaceutical formulations without interference from the excipients. Moreover the HPLC method was successfully used in the determination of both drugs in spiked human plasma.

     

纳米晶体锗（Nc—Ge）合成方法介绍

评述了纳米晶体锗的合成方法     

Determination of Underivatized Polyamines: A Review of Analytical Methods and Applications

Putrescine, cadaverine, spermidine, and spermine are ubiquitous polyamines that are essentially found in diverse organisms (e.g., bacteria, fungi), animals, and higher plants. Analysis of these analytes is traditionally performed either by chromatographic or electrophoretic techniques. The majority of assays employ liquid chromatography with fluorimetric detection either with pre-column or post-column derivatization. However, the derivatization procedures have several disadvantages to the whole analytical process. This article describes the analytical method developments in the determination of underivatized polyamines. This includes flow injection analysis, high performance liquid chromatography (using conductivity, condensation nucleation light scattering, chemiluminescence, indirect fluorescence, and mass spectrometric detection) and electromigration methods. The reported systems are essentially based on the work developed by the authors since 1995. A comparison of the methods highlighting their main advantages and disadvantages and sensitivity was also provided. The most promising system seems to be the liquid chromatography-tandem mass spectrometric due to its high sensitivity and specificity.     

Molecular Forcefield Methods for Describing Energetic Molecular Crystals: A Review

Energetic molecular crystals are widely applied for military and civilian purposes, and molecular forcefields (FF) are indispensable for treating the microscopic issues therein. This article reviews the three types of molecular FFs that are applied widely for describing energetic crystals—classic FFs, consistent FFs, and reactive FFs (ReaxFF). The basic principle of each type of FF is briefed and compared, with the application introduced, predicting polymorph, morphology, thermodynamics, vibration spectra, thermal property, mechanics, and reactivity. Finally, the advantages and disadvantages of these FFs are summarized, and some directions of future development are suggested.     

Stability-Indicating Chromatographic Methods for Simultaneous Determination of Mosapride and Pantoprazole in Pharmaceutical Dosage Form and Plasma Samples

Simple, sensitive, selective, precise, and stability-indicating thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) methods for the determination of mosapride and pantoprazole in pharmaceutical tablets were developed and validated as per the International Conference on Harmonization guidelines. The TLC method employs aluminum TLC plates precoated with silica gel 60F₂₅₄ as the stationary phase and ethyl acetate/methanol/toluene (4:1:2, v/v/v) as the mobile phase to give compact spots for mosapride (R _f 0.73) and pantoprazole (R _f 0.45) separated from their degradation products; the chromatogram was scanned at 276 nm. The HPLC method utilizes a C18 column and a mobile phase consisting of acetonitrile/methanol/20 mM ammonium acetate (4:2:4, v/v/v) at a flow rate of 1.0 mL min^?1 for the separation of mosapride (t _R 11.4) and pantoprazole (t _R 4.4) from their degradation products. Quantitation was achieved with UV detection at 280 nm. The same HPLC method was successfully used in performing calibrations in lower concentration ranges for both drugs in human plasma using ezetimibe as internal standard. The methods were validated in terms of accuracy, precision, linearity, limits of detection, and limits of quantification. Mosapride and pantoprazole were exposed to acid hydrolysis and then analyzed by the proposed methods. As the methods could effectively separate the drugs from their degradation products, these techniques can be employed as stability-indicating methods that have been successively applied to pharmaceutical formulations without interference from the excipients. Moreover the HPLC method was successfully used in the determination of both drugs in spiked human plasma.